An Improvised Explosive Device (IED) is an explosive device that is cobbled together (or “improvised”) for example, from commercial or military explosives, homemade explosives, military ordnance and/or ordnance components, typically by terrorists, guerrillas or commando forces for use in unconventional warfare. IEDs may be implemented for the purpose of causing death or injury to civilian or military personnel, to destroy or incapacitate structural targets or simply to harass or distract an opponent. IEDs may comprise conventional high-explosive charges alone or in combination with toxic chemicals, biological agents or nuclear material. IEDs may be physically placed at or near a pre-determined target or carried by person or vehicle toward a predetermined target or target of opportunity.
As will be appreciated, the design of construction of an IED and the manner and tactics for which a terrorist may employ an IED may vary depending on the available materials and sophistication of the designer. As such, a variety of different triggering mechanisms could be used to trigger detonation of IEDs. It is contemplated that certain IEDs, either by design or by nature of the triggering mechanism, may detonate responsive to exposure to radiated sound energy of a certain type or characteristic. For example and without limitation, high-intensity sounds or “noise prints” having a characteristic sound pattern could be used to trigger detonation of IEDs. It is a concern that these tactics can be used to trigger bombings against civilian and military targets throughout the world. Accordingly, there is a need for precautionary measures to respond to this threat.